1. Lie Detector

In the episode "Lovey's Secret Admirer," Mrs. Howell keeps receiving love notes. To find out who is sending them, the Professor puts together a lie detector out of the ship's horn and batteries from the radio. 

2. Geiger counter

When a meteor crashes onto the island in season two, the Professor whips up a bamboo Geiger counter. To the dismay of everyone on the island, he concludes the meteor's cosmic rays will make everyone age quickly and die within a week. 

3. Electric generator

This is the invention that allowed many more to be created. To create the energy needs for some of his more impressive inventions, the Professor creates a pedal-powered generator by using a bike, wires, and the generator from the ship.

4. Sewing machine

Thanks to the Professor, everyone on the island had stylish clothes that fit properly.

5. Washing machine

Speaking of clothes, everyone on the island had clean ones because the Professor took the time to build a washing machine. And it must have been a good one... How else can you explain everyone's vibrant clothing?

6. Telegraph

Perhaps one of the Professor's biggest engineering feats, the telegraph required four people to pedal on a bike to generate the energy needed to send a signal. 

7. Hot air balloon

Instead of fixing the ship, the Professor decides to build an entirely new device to get off the island. In "Gilligan Meets Jungle Boy," the Professor constructs a hot air balloon so someone can get help. But his plans are thwarted by a young Kurt Russell, who is the only one to make it off the island in the balloon. 

8. Jetpack fuel

If the hot air balloon didn't work to get the castaways off the island, then surely a jetpack will. When the mysterious jetpack washes ashore, the Professor tries to create fuel so they can use it to their advantage. 

9. Battery charger

When you put coconut shells and saltwater together, you get... well... saltwater inside of a coconut shell.

But if you're the Professor, you get a batter charger. By utilizing those two items, along with pennies and hairpins, he constructed a battery charger for the island's radio. 

10. Bomb

When a volcanic eruption looms over the island, the Professor does what anyone would do... build a bomb to relieve the pressure. The Professor somehow finds nitroglycerin to build the bomb, which Gilligan thinks he accidentally drank. 

11. Roulette wheel

Though it's not one of the flashiest inventions, the roulette wheel constructed by the Professor in "Three Million Dollars More of Less" shows the Professor has more hobbies (i.e. gambling) than just building things.